(1) Field of the Invention
This invention relates generally to loudspeaker systems and relates more specifically to methods and apparatus for computing a metric value for loudspeaker protection.
(2) Description of the Prior Art
It is well known that loudspeakers can be damaged due to overheating when driven at high output levels, especially for audio applications that contain high frequency components. Current practice is to prevent loudspeaker damage by simply hard or soft limiting the maximum power output to the loudspeaker.
As a result the maximum sound pressure level (SPL) that can be produced is severely limited even if the actual temperature of the loudspeaker is below the damage threshold. More advanced systems incorporate a simple thermal model of the loudspeaker which may not be accurate, or a temperature sensor to activate the limiter, which introduces additional complexity and cost.
Therefore it would be desirable to achieve a method for obtaining a threshold value for loudspeaker protection, based on instantaneous voltage and current measurements.
It is also challenge for engineers to achieve loudspeaker protection at reasonable cost without requiring additional devices to the loudspeaker.